1. Field of the Invention
The invention relates to methods for producing aesthetic decorative metal patterns on glass, plastic or other electrically non-conductive materials and articles with such patterns produced by the methods of the invention.
2. Description of Related Art
Decorative overlays of silver and other metals have been applied to glass and other electrically non-conductive surfaces in the past, but these have not been entirely satisfactory because of the relatively poor adhesion of the metal plating to the glass or other non-conductive material such as plastic. Generally speaking, such metal patterns have been applied by hand, e.g. with brushes, by silk screening, or by metal leaf. The metal is held on the non-conductive surface by an adhesive, and when the surface of the metal is rough, such as with brush application, the metal cannot be adequately polished without damaging the metal pattern.
The metal pattern has also been applied by electroplating, and in such method, conductive areas in the shape of the desired pattern are formed on the base, non-conductive material or substrate. Such areas must withstand the inherent stresses of the electric current and the plating solutions, e.g. acidic or cyanic solutions, and maintain a strong bond with the base material after being subjected to such solutions.
To be visually and artistically acceptable, the metal pattern must have sharp boundaries and should cover at least 50% of the decorated surface when applied as a decoration to various decorative items, such as, vases, bowls, decanters, plastic pens, picture frames, paper weights, coasters, etc.
It is known in the art to apply a rough, porous metal-glass or metal-ceramic frit with an abrasive to a non-conductive base material or substrate in a pattern and to fuse the mixture to the substrate for the purpose of providing heating elements on glass. See U.S. Pat. No. 3,703,445. As described in the patent, surface metal is applied to the so applied and fused frit pattern by electroless deposit, and the frit pattern, by itself, is rough and is not sufficiently conductive for electroplating. Therefore, the frit pattern must be subjected to electroless deposit before electroplating. Furthermore, the patent teaches that the use of masking is unsatisfactory.